The optimal succinylcholine dose for intubating emergency patients: retrospective comparative study

Background : Succinylcholine remains the drug of choice for satisfactory rapid-sequence tracheal intubation. It is not clear from the literature why the 1 mg/kg dose of succinylcholine has been traditionally used. The effective dose (ED95) of succinylcholine is less than 0.3 mg/kg. The dose of 1 mg/kg represents 3.5 to 4 times the ED95. Objectives : To compare the effect of the traditionally used 1 mg/kg of succinylcholine with lower doses of 0.6 mg/kg and 0.45 mg/kg on intubation condition regarding the onset time, duration of action, duration of abdominal fasciculation, and the intubation grading. Methods : This retrospective comparative study was carried into three groups of ASA III & IV (American Society of Anesthesiologist's Physical Status III and IV) non-prepared emergency patients who were intubated at emergency department of Hamad General Hospital, Doha, Qatar during January 1st 2007 to August 31, 2010. The Institutional Research Board (IRB) approval was obtained. This study was limited to 88 patients who received fentanyl 1 µg/kg followed by etomidate 0.3 mg/kg intravenously as induction agents and succinylcholine as a muscle relaxant agent in doses of 0.45 mg/kg, 0.6 mg/kg, or 1 mg/kg. Results : Increasing the succinylcholine dosage shortened the onset time, prolonged the duration of action, and prolonged the duration of abdominal fasciculation significantly (P<.001). Tracheal intubation was 100% successful in the three groups of patients. Conclusion : Succinylcholine dose of 0.45 mg/kg provides an optimal intubation condition in ASA III & IV emergency non-prepared patients. Duration of action of succinylcholine is dose dependent; reducing the dose allows a more rapid return of spontaneous respiration and airway reflexes

First report of field evolved resistance to agrochemicals in dengue mosquito, Aedes albopictus (Diptera: Culicidae), from Pakistan

<p>Abstract</p> <p>Background</p> <p>Agrochemicals have been widely used in Pakistan for several years. This exposes mosquito populations, particularly those present around agricultural settings, to an intense selection pressure for insecticide resistance. The aim of the present study was to investigate the toxicity of representative agrochemicals against various populations of <it>Aedes albopictus </it>(Skuse) collected from three different regions from 2008-2010.</p> <p>Results</p> <p>For organophosphates and pyrethroids, the resistance ratios compared with susceptible Lab-PK were in the range of 157-266 fold for chlorpyrifos, 24-52 fold for profenofos, 41-71 fold for triazofos, and 15-26 fold for cypermethrin, 15-53 fold for deltamethrin and 21-58 fold for lambdacyhalothrin. The resistance ratios for carbamates and new insecticides were in the range of 13-22 fold for methomyl, 24-30 fold for thiodicarb, and 41-101 fold for indoxacarb, 14-27 fold for emamectin benzoate and 23-50 fold for spinosad. Pair wise comparisons of the log LC_50sof insecticides revealed correlation among several insecticides, suggesting a possible cross resistance mechanism. Moreover, resistance remained stable across 3 years, suggesting field selection for general fitness had also taken place for various populations of <it>Ae. albopictus</it>.</p> <p>Conclusion</p> <p>Moderate to high level of resistance to agrochemicals in Pakistani field populations of <it>Ae. albopictus </it>is reported here first time. The geographic extent of resistance is unknown but, if widespread, may lead to problems in future vector control.</p